The Centre of Attention: A Powerful Radio Galaxy Pinpoints a Near-infrared-dark Protocluster at <i>z</i> ∼ 3.9
Bibliographic record
Abstract
Abstract We report the discovery of a z ∼ 3.9 protocluster identified from Atacama Large Millimeter/submillimeter Array Band 3 spectral scans of a bright radio source selected from the Galactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. Extended CO(4–3) and [C I] (3 P 1 → 3 P 0) line emission was detected in GLEAM J005332−325630 confirming it to be a z = 3.879 powerful radio galaxy with luminosity L 500 MHz = 1.3 × 1028 W Hz−1. This source is part of a sample of candidate high-redshift radio galaxies with bright radio fluxes, S 150 MHz > 0.1 Jy, but host galaxies with K s (AB) ≳ 23 mag. The molecular gas associated with the radio galaxy host has two kinematically separate components, likely infalling and indicative of a recent interaction or merger with another galaxy. One 100 GHz continuum source ∼120 pkpc away is found to have both CO(4–3) and [C I] (3 P 1 → 3 P 0) emission lines and a further five protocluster members are identified from CO(4–3) emission alone, all at a similar redshift (Δv < 700 km s−1) and within a radius of 1. ′ 1 . Using photometry from the High Acuity Widefield K-band Imager K s band and the Dark Energy Survey g, r, i, z, and Y bands, we find this protocluster harbours a rare, optically dark, very massive M * ∼ 1012 M ⊙ galaxy. Comparisons with the TNG300 cosmological simulation puts this galaxy in a dark matter (DM) halo of M DM ∼ 3 × 1013 M ⊙, which will evolve into a Coma-like DM halo (M DM ∼ 1015 M ⊙) by the present day.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".